Truxton II without a doubt!! I made it to stage #3 and it was a great achievement, I don't think a sane human being can make it to the last stage! the game is way beyond ridiculous and unfair, enemies constantly shooting at coming at you very fast, weak weapons and very scarce power ups. The bosses are insanely unfair and there's not a single second of the game when you can relax, not even between levels, other games worth mentioning are Ghosts n Goblins, Hagane, Knights of the round, Ikaruga and most of the retro shmups.

Download for my emulators